A programmer writes a JOIN statement to identify the records for joining. If the evaluated predicate is true, the combined record is then produced in the expected format, a record set or a temporary table. Relational databases are often normalized to eliminate duplication of information when objects may have one-to-many relationships. For example, a Department may be associated with many different Employees. Note: In the Employee table above, the employee "John" has not been assigned to any department yet. This is the SQL to create the aforementioned tables. CROSS JOIN returns the Cartesian product of rows from tables in the join. Example of an explicit cross join: SELECT *FROM employee CROSS JOIN department; Example of an implicit cross join: SELECT *FROM employee, department; The cross join does not apply any predicate to filter records from the joined table. In the SQL:2011 standard, cross joins are part of the optional F401, "Extended joined table", package. Sybase supports the syntax:
